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feat: implement double buffering

This commit is contained in:
Rekai Nyangadzayi Musuka 2022-05-17 06:53:37 -03:00
parent 660c8a2d62
commit daf977ef06
2 changed files with 54 additions and 12 deletions
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2
src/main.zig
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@ -169,7 +169,7 @@ pub fn main() anyerror!void {
}
// FIXME: Is it OK just to copy the Emulator's Frame Buffer to SDL?
const buf_ptr = cpu.bus.ppu.framebuf.ptr;
const buf_ptr = cpu.bus.ppu.framebuf.get(.Renderer).ptr;
_ = SDL.SDL_UpdateTexture(texture, null, buf_ptr, framebuf_pitch);
_ = SDL.SDL_RenderCopy(renderer, texture, null, null);
SDL.SDL_RenderPresent(renderer);

64
src/ppu.zig
View File

@ -35,7 +35,7 @@ pub const Ppu = struct {
palette: Palette,
oam: Oam,
sched: *Scheduler,
framebuf: []u8,
framebuf: FrameBuffer,
alloc: Allocator,
scanline_sprites: [128]?Sprite,
@ -45,15 +45,15 @@ pub const Ppu = struct {
// Queue first Hblank
sched.push(.Draw, sched.tick + (240 * 4));
const framebuf = try alloc.alloc(u8, framebuf_pitch * height);
std.mem.set(u8, framebuf, 0);
const framebufs = try alloc.alloc(u8, (framebuf_pitch * height) * 2);
std.mem.set(u8, framebufs, 0);
return Self{
.vram = try Vram.init(alloc),
.palette = try Palette.init(alloc),
.oam = try Oam.init(alloc),
.sched = sched,
.framebuf = framebuf,
.framebuf = FrameBuffer.init(framebufs),
.alloc = alloc,
// Registers
@ -68,7 +68,7 @@ pub const Ppu = struct {
}
pub fn deinit(self: Self) void {
self.alloc.free(self.framebuf);
self.framebuf.deinit(self.alloc);
self.vram.deinit();
self.palette.deinit();
self.oam.deinit();
@ -295,7 +295,7 @@ pub const Ppu = struct {
// If there are any nulls present in self.scanline_buf it means that no background drew a pixel there, so draw backdrop
for (self.scanline_buf) |maybe_px, i| {
const bgr555 = if (maybe_px) |px| px else self.palette.getBackdrop();
std.mem.copy(u8, self.framebuf[fb_base + i * @sizeOf(u32) ..][0..4], &intToBytes(u32, toRgba8888(bgr555)));
std.mem.copy(u8, self.framebuf.get(.Emulator)[fb_base + i * @sizeOf(u32) ..][0..4], &intToBytes(u32, toRgba8888(bgr555)));
}
// Reset Current Scanline Pixel Buffer and list of fetched sprites
@ -319,7 +319,7 @@ pub const Ppu = struct {
// If there are any nulls present in self.scanline_buf it means that no background drew a pixel there, so draw backdrop
for (self.scanline_buf) |maybe_px, i| {
const bgr555 = if (maybe_px) |px| px else self.palette.getBackdrop();
std.mem.copy(u8, self.framebuf[fb_base + i * @sizeOf(u32) ..][0..4], &intToBytes(u32, toRgba8888(bgr555)));
std.mem.copy(u8, self.framebuf.get(.Emulator)[fb_base + i * @sizeOf(u32) ..][0..4], &intToBytes(u32, toRgba8888(bgr555)));
}
// Reset Current Scanline Pixel Buffer and list of fetched sprites
@ -341,7 +341,7 @@ pub const Ppu = struct {
// If there are any nulls present in self.scanline_buf it means that no background drew a pixel there, so draw backdrop
for (self.scanline_buf) |maybe_px, i| {
const bgr555 = if (maybe_px) |px| px else self.palette.getBackdrop();
std.mem.copy(u8, self.framebuf[fb_base + i * @sizeOf(u32) ..][0..4], &intToBytes(u32, toRgba8888(bgr555)));
std.mem.copy(u8, self.framebuf.get(.Emulator)[fb_base + i * @sizeOf(u32) ..][0..4], &intToBytes(u32, toRgba8888(bgr555)));
}
// Reset Current Scanline Pixel Buffer and list of fetched sprites
@ -356,7 +356,7 @@ pub const Ppu = struct {
var i: usize = 0;
while (i < width) : (i += 1) {
const bgr555 = self.vram.read(u16, vram_base + i * @sizeOf(u16));
std.mem.copy(u8, self.framebuf[fb_base + i * @sizeOf(u32) ..][0..4], &intToBytes(u32, toRgba8888(bgr555)));
std.mem.copy(u8, self.framebuf.get(.Emulator)[fb_base + i * @sizeOf(u32) ..][0..4], &intToBytes(u32, toRgba8888(bgr555)));
}
},
0x4 => {
@ -367,7 +367,7 @@ pub const Ppu = struct {
// Render Current Scanline
for (self.vram.buf[vram_base .. vram_base + width]) |byte, i| {
const bgr555 = self.palette.read(u16, @as(u16, byte) * @sizeOf(u16));
std.mem.copy(u8, self.framebuf[fb_base + i * @sizeOf(u32) ..][0..4], &intToBytes(u32, toRgba8888(bgr555)));
std.mem.copy(u8, self.framebuf.get(.Emulator)[fb_base + i * @sizeOf(u32) ..][0..4], &intToBytes(u32, toRgba8888(bgr555)));
}
},
0x5 => {
@ -384,7 +384,7 @@ pub const Ppu = struct {
const bgr555 =
if (scanline < m5_height and i < m5_width) self.vram.read(u16, vram_base + i * @sizeOf(u16)) else self.palette.getBackdrop();
std.mem.copy(u8, self.framebuf[fb_base + i * @sizeOf(u32) ..][0..4], &intToBytes(u32, toRgba8888(bgr555)));
std.mem.copy(u8, self.framebuf.get(.Emulator)[fb_base + i * @sizeOf(u32) ..][0..4], &intToBytes(u32, toRgba8888(bgr555)));
}
},
else => std.debug.panic("[PPU] TODO: Implement BG Mode {}", .{bg_mode}),
@ -456,6 +456,8 @@ pub const Ppu = struct {
} else {
// Transitioning to a Vblank
if (scanline == 160) {
self.framebuf.swap(); // Swap FrameBuffers
self.dispstat.vblank.set();
if (self.dispstat.vblank_irq.read()) {
@ -884,3 +886,43 @@ fn toRgba8888Talarubi(bgr555: u16) u32 {
return @floatToInt(u32, out_r) << 24 | @floatToInt(u32, out_g) << 16 | @floatToInt(u32, out_b) << 8 | 0xFF;
}
// Double Buffering Implementation
const FrameBuffer = struct {
const Self = @This();
buf: [2][]u8,
original: []u8,
current: u1,
// TODO: Rename
const Device = enum {
Emulator,
Renderer,
};
pub fn init(bufs: []u8) Self {
std.debug.assert(bufs.len == framebuf_pitch * height * 2);
const front = bufs[0 .. framebuf_pitch * height];
const back = bufs[framebuf_pitch * height ..];
return .{
.buf = [2][]u8{ front, back },
.original = bufs,
.current = 0,
};
}
fn deinit(self: Self, alloc: Allocator) void {
alloc.free(self.original);
}
pub fn swap(self: *Self) void {
self.current = ~self.current;
}
pub fn get(self: *Self, comptime dev: Device) []u8 {
return self.buf[if (dev == .Emulator) self.current else ~self.current];
}
};